Large anomalous Hall effect and \textit{A}-phase in hexagonal polar magnet Gd$_3$Ni$_8$Sn$_4$

TL;DR

This study reports a large intrinsic anomalous Hall effect and skyrmion A-phase in the polar magnet Gd$_3$Ni$_8$Sn$_4$, highlighting its potential for exploring topological magnetic phenomena in strongly correlated systems.

Contribution

It provides the first experimental evidence of topological magnetic phases and a significant anomalous Hall effect in a hexagonal polar magnet with $C_{6v}$ symmetry.

Findings

Observation of large intrinsic anomalous Hall effect.

Detection of skyrmion A-phase through topological Hall response.

Correlation of Hall effect with magnetic and transport anomalies.

Abstract

While recent theoretical studies have positioned noncollinear polar magnets with $C_{nv}$ symmetry as compelling candidates for realizing topological magnetic phases and substantial intrinsic anomalous Hall conductivity, experimental realizations of the same in strongly correlated systems remain rare. Here, we present a large intrinsic anomalous Hall effect and extended topological magnetic ordering in Gd$_3$Ni$_8$Sn$_4$ with hexagonal $C_{6v}$ symmetry. Observation of topological Hall response, corroborated by metamagnetic anomalies in isothermal magnetization, peak/hump features in field-evolution of ac susceptibility and longitudinal resistivity, attests to the stabilization of skyrmion $A$-phase. The anomalous Hall effect is quantitatively accounted for by the intrinsic Berry curvature-mediated mechanism. Our results underscore polar magnets as a promising platform to investigate a plethora of emergent electrodynamic responses rooted in the interplay between magnetism and topology.